Mixed electoral systems: The best of both worlds or the worst of both?

Abstract

Mixed electoral systems combine majoritarian and proportional rules within a single institutional framework, promising what Shugart and Wattenberg (2001) called "the best of both worlds": local accountability alongside representational fairness. This article surveys the family of mixed systems—parallel, compensatory, proportional, and combined—and examines whether their constitutional promise has been fulfilled. Simulations of seat allocation under alternative mixed designs demonstrate that these systems generate markedly different seat distributions, undermining any unified claim about their representational properties. A systematic analysis of the paradoxes that have emerged over a quarter century of practice—excessive complexity, decoy parties, manipulative coalition coordination, uncontrolled parliamentary growth, and "zombie" legislators—reveals that strategic actors routinely exploit the gap between constitutional aspiration and institutional detail. We conclude by assessing how variation in the constitutional entrenchment of mixed systems shapes both the scope for manipulation and the capacity for reform. A Glossary of key concepts is included as an Appendix.